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Bug #46047
open[rgw] resizing pg_num/pgp_num causes excessive osd traffic on get_omap_iterator
Status:
New
Priority:
Normal
Assignee:
-
Target version:
-
% Done:
0%
Source:
Tags:
Backport:
Regression:
No
Severity:
3 - minor
Reviewed:
Affected Versions:
ceph-qa-suite:
Pull request ID:
Crash signature (v1):
Crash signature (v2):
Description
Autoscaler tuned the .index pool for rgw to 8 pgs (we have 40 OSDs) which causes a bit of a hot-spot issue so I thought about increasing it to 32 (via setting autoscaler bias.
That caused any OSD involved in to basically go to 100% IO load (stuck in IO wait mostly), after enabling bluestore debug I got:
2020-06-17T12:35:05.700+0200 7f80694c4700 10 bluestore(/var/lib/ceph/osd/ceph-20) omap_get_header 10.51_head oid #10:8b1a34d8:::.dir.88d4f221-0da5-444d-81a8-517771278350.454759.8.214:head# = 0 2020-06-17T12:35:05.700+0200 7f80694c4700 10 bluestore(/var/lib/ceph/osd/ceph-20) get_omap_iterator 10.51_head #10:8b1a34d8:::.dir.88d4f221-0da5-444d-81a8-517771278350.454759.8.214:head# 2020-06-17T12:35:05.700+0200 7f80694c4700 10 bluestore(/var/lib/ceph/osd/ceph-20) get_omap_iterator 10.51_head #10:8b1a34d8:::.dir.88d4f221-0da5-444d-81a8-517771278350.454759.8.214:head# 2020-06-17T12:35:05.700+0200 7f80694c4700 10 bluestore(/var/lib/ceph/osd/ceph-20) get_omap_iterator 10.51_head #10:8b1a34d8:::.dir.88d4f221-0da5-444d-81a8-517771278350.454759.8.214:head# 2020-06-17T12:35:05.700+0200 7f80694c4700 10 bluestore(/var/lib/ceph/osd/ceph-20) get_omap_iterator 10.51_head #10:8b1a34d8:::.dir.88d4f221-0da5-444d-81a8-517771278350.454759.8.214:head# 2020-06-17T12:35:05.704+0200 7f80694c4700 10 bluestore(/var/lib/ceph/osd/ceph-20) get_omap_iterator 10.51_head #10:8b1a34d8:::.dir.88d4f221-0da5-444d-81a8-517771278350.454759.8.214:head# 2020-06-17T12:35:05.704+0200 7f80694c4700 10 bluestore(/var/lib/ceph/osd/ceph-20) get_omap_iterator 10.51_head #10:8b1a34d8:::.dir.88d4f221-0da5-444d-81a8-517771278350.454759.8.214:head# 2020-06-17T12:35:05.704+0200 7f80694c4700 10 bluestore(/var/lib/ceph/osd/ceph-20) get_omap_iterator 10.51_head #10:8b1a34d8:::.dir.88d4f221-0da5-444d-81a8-517771278350.454759.8.214:head# 2020-06-17T12:35:05.704+0200 7f80694c4700 10 bluestore(/var/lib/ceph/osd/ceph-20) get_omap_iterator 10.51_head #10:8b1a34d8:::.dir.88d4f221-0da5-444d-81a8-517771278350.454759.8.214:head# 2020-06-17T12:35:05.704+0200 7f80694c4700 10 bluestore(/var/lib/ceph/osd/ceph-20) omap_get_header 10.51_head oid #10:8b0d75b0:::.dir.88d4f221-0da5-444d-81a8-517771278350.454759.8.222:head# = 0 2020-06-17T12:35:05.704+0200 7f80694c4700 10 bluestore(/var/lib/ceph/osd/ceph-20) get_omap_iterator 10.51_head #10:8b0d75b0:::.dir.88d4f221-0da5-444d-81a8-517771278350.454759.8.222:head# 2020-06-17T12:35:05.704+0200 7f80694c4700 10 bluestore(/var/lib/ceph/osd/ceph-20) get_omap_iterator 10.51_head #10:8b0d75b0:::.dir.88d4f221-0da5-444d-81a8-517771278350.454759.8.222:head# 2020-06-17T12:35:05.704+0200 7f80694c4700 10 bluestore(/var/lib/ceph/osd/ceph-20) get_omap_iterator 10.51_head #10:8b0d75b0:::.dir.88d4f221-0da5-444d-81a8-517771278350.454759.8.222:head# 2020-06-17T12:35:05.704+0200 7f80694c4700 10 bluestore(/var/lib/ceph/osd/ceph-20) get_omap_iterator 10.51_head #10:8b0d75b0:::.dir.88d4f221-0da5-444d-81a8-517771278350.454759.8.222:head# 2020-06-17T12:35:05.704+0200 7f80694c4700 10 bluestore(/var/lib/ceph/osd/ceph-20) get_omap_iterator 10.51_head #10:8b0d75b0:::.dir.88d4f221-0da5-444d-81a8-517771278350.454759.8.222:head# 2020-06-17T12:35:05.704+0200 7f80694c4700 10 bluestore(/var/lib/ceph/osd/ceph-20) get_omap_iterator 10.51_head #10:8b0d75b0:::.dir.88d4f221-0da5-444d-81a8-517771278350.454759.8.222:head# 2020-06-17T12:35:05.708+0200 7f80694c4700 10 bluestore(/var/lib/ceph/osd/ceph-20) get_omap_iterator 10.51_head #10:8b0d75b0:::.dir.88d4f221-0da5-444d-81a8-517771278350.454759.8.222:head# 2020-06-17T12:35:05.708+0200 7f80694c4700 10 bluestore(/var/lib/ceph/osd/ceph-20) get_omap_iterator 10.51_head #10:8b0d75b0:::.dir.88d4f221-0da5-444d-81a8-517771278350.454759.8.222:head# 2020-06-17T12:35:05.716+0200 7f806d4cc700 10 bluestore(/var/lib/ceph/osd/ceph-20) omap_get_header 10.51_head oid #10:8b5ed205:::.dir.88d4f221-0da5-444d-81a8-517771278350.454759.8.151:head# = 0 2020-06-17T12:35:05.716+0200 7f806d4cc700 10 bluestore(/var/lib/ceph/osd/ceph-20) get_omap_iterator 10.51_head #10:8b5ed205:::.dir.88d4f221-0da5-444d-81a8-517771278350.454759.8.151:head# 2020-06-17T12:35:05.716+0200 7f806d4cc700 10 bluestore(/var/lib/ceph/osd/ceph-20) get_omap_iterator 10.51_head #10:8b5ed205:::.dir.88d4f221-0da5-444d-81a8-517771278350.454759.8.151:head# 2020-06-17T12:35:05.720+0200 7f806d4cc700 10 bluestore(/var/lib/ceph/osd/ceph-20) get_omap_iterator 10.51_head #10:8b5ed205:::.dir.88d4f221-0da5-444d-81a8-517771278350.454759.8.151:head# 2020-06-17T12:35:05.720+0200 7f806d4cc700 10 bluestore(/var/lib/ceph/osd/ceph-20) get_omap_iterator 10.51_head #10:8b5ed205:::.dir.88d4f221-0da5-444d-81a8-517771278350.454759.8.151:head# 2020-06-17T12:35:05.720+0200 7f806d4cc700 10 bluestore(/var/lib/ceph/osd/ceph-20) get_omap_iterator 10.51_head #10:8b5ed205:::.dir.88d4f221-0da5-444d-81a8-517771278350.454759.8.151:head# 2020-06-17T12:35:05.720+0200 7f806d4cc700 10 bluestore(/var/lib/ceph/osd/ceph-20) get_omap_iterator 10.51_head #10:8b5ed205:::.dir.88d4f221-0da5-444d-81a8-517771278350.454759.8.151:head# 2020-06-17T12:35:05.720+0200 7f806d4cc700 10 bluestore(/var/lib/ceph/osd/ceph-20) get_omap_iterator 10.51_head #10:8b5ed205:::.dir.88d4f221-0da5-444d-81a8-517771278350.454759.8.151:head# 2020-06-17T12:35:05.720+0200 7f806d4cc700 10 bluestore(/var/lib/ceph/osd/ceph-20) get_omap_iterator 10.51_head #10:8b5ed205:::.dir.88d4f221-0da5-444d-81a8-517771278350.454759.8.151:head#
and similar for rest of the pgs
Resizing back to original 8 PGs resolved the performance issue
Updated by Mariusz Gronczewski almost 4 years ago
NVM, same behaviour, I just thought load dropped because I didn't look at all nodes
cluster itself is getting much smaller (few thousand requests per second for files <1MB) traffic, yet load on OSDs involved in rgw index is very high
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